It is known that ethylene is involved in plant senescence and plant stress reactions. For this reason, plant growth regulators (PGRs) that inhibit or regulate the production of ethylene or control its action in plants have been developed in an effort to improve the economic yield of agricultural crops.
In practice, such PGRs may be applied to plants in a variety of methods including different formulations. Of these various methods, use of liquid and dry compositions are the most common. The particular formulation desired and the resulting effect on the physiology of plant growth will greatly depend upon the PGR used, the plant species to be treated, environmental conditions, the geographical area and the climate of the area at the time of treatment.
Certain obstacles make the actual use of some PGRs impractical in certain circumstances. For example, one group of ethylene inhibitor PGRs are the cyclopropenes which are mainly gaseous small molecules. One example of such a cyclopropene PGR is 1-methylcyclopropene (1-MCP), which is often employed in the form of a complex with a molecular encapsulating agent as a way of more conveniently storing, transporting and delivering the 1-MCP to a target plant or to soil. Contact between such 1-MCP complexes and water will quickly release 1-MCP gas from the complex in order to accomplish delivery of the PGR to the target.
A challenge arises where a user of a concentrate formulation containing a 1-MCP complex wishes to dilute the formulation in water (for example in a spray tank) in order to form an aqueous spray composition. Such aqueous agrochemical spray compositions are widely used in agriculture, but their performance with 1-MCP complexes sometimes can be limited by the tendency for the 1-MCP complex to degrade in a spray tank on exposure to water. This can result in reduced efficacy and in an unacceptable build-up of the 1-MCP gas in the head-space of the spray tank.
In addition, due to the relatively complex supply chain for crop protection agents, such 1-MCP complex containing concentrates can be stored for long periods and may be subjected during storage and shipping to extreme temperature variations, high-shear, repetitive vibration patterns and to humidity. Such supply chain conditions can increase the likelihood of formulation failure due to, for example, water mediated degradation and stability problems.
Considering the variety of conditions and special situations under which 1-MCP complex containing concentrates are stored, shipped and used around the world, there remains a need for concentrate formulations of 1-MCP that provide stability benefits under at least some of those conditions and situations. There is a further need for such concentrate formulations having high loading, that are stable for a period of time when diluted with water under a wide range of field conditions, and wherein an end user may control the release rate of the 1-MCP into the application site from a concentrate or dilute spray formulation.